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Your Layout and Models => Electronics => Topic started by: Railwaygun on December 09, 2019, 03:42:42 PM

Title: Resistor colour codes
Post by: Railwaygun on December 09, 2019, 03:42:42 PM
For the electrically challenged
Title: Re: Resistor colour codes
Post by: Nigel Cliffe on December 09, 2019, 04:33:24 PM
Or, just use a Digital Multimeter's resistance scale to read the value from the component before use.   

I have a couple of meters on the bench.  I have two because they were "two for 5".   Prices have gone up a little since I bought them, so perhaps "two for 10". 



- Nigel
Title: Re: Resistor colour codes
Post by: Dorsetmike on December 09, 2019, 04:47:22 PM
Handy mnemonic for colour code for 0-9
   0     1        2             3          4      5        6        7       8       9
Billy   Brown revives     on      your    gin    but  prefers good  whiskey
Black Brown   Red    Orange  yellow Green Blue Purple   Grey  White

For tolerance Gold = 5%  Silver 10%  unmarked 20% 
(A few better tolerance ones may have 1%-4% by the above colour code.)

( there is also a rude version)

Title: Re: Resistor colour codes
Post by: ntpntpntp on December 09, 2019, 04:51:22 PM
I reckon I know the colour codes fairly well as I've been putting circuits together since I was a young lad in the 70s, but yes I do check with a multimeter   :D   

With all the strips of resistors I buy I write the value on the strip, and organize in trays so that for example 56R, 560R, 5k6, 56k, 560k etc. strips all go in the same tray.
Title: Re: Resistor colour codes
Post by: chrism on December 09, 2019, 04:53:39 PM
Handy mnemonic for colour code for 0-9
   0     1        2             3          4      5        6        7       8       9
Billy   Brown revives     on      your    gin    but  prefers good  whiskey
Black Brown   Red    Orange  yellow Green Blue Purple   Grey  White

For tolerance Gold = 5%  Silver 10%  unmarked 20% 
(A few better tolerance ones may have 1%-4% by the above colour code.)

( there is also a rude version)

I only know the rude version   :-[

Mind you, it only works if 7 is given its correct colour name  :P
Title: Re: Resistor colour codes
Post by: ShakyZZR on December 09, 2019, 05:22:33 PM
( there is also a rude version)

I only know the rude version   :-[

Mind you, it only works if 7 is given its correct colour name  :P

Yes, I remember being at Otley BT training school in the early eighties and getting told the rude version. If it was repeated anywhere nowadays you'd have the coppers knocking at your door  :sorrysign:
Title: Re: Resistor colour codes
Post by: Dorsetmike on December 09, 2019, 05:37:36 PM
Quote
Mind you, it only works if 7 is given its correct colour name 

Purple/violet  so in the polite version substitute prefers for values it still works.
Title: Re: Resistor colour codes
Post by: Ditape on December 09, 2019, 05:44:16 PM
I too was taught the :censored: non PC version using Violet not purple back in the early 70's at Artificer training in the RN.

 :censored: Boys  :censored: our young girls but   :censored: go without.
Title: Re: Resistor colour codes
Post by: gawain on December 09, 2019, 06:27:25 PM
The version I was taught at Civilian Tech School RAF Sealand replaced Boys with B:censored:ds.
Title: Re: Resistor colour codes
Post by: ShakyZZR on December 09, 2019, 08:06:08 PM
The version I was taught at Civilian Tech School RAF Sealand replaced Boys with B:censored:ds.

Same 'ere  :goggleeyes:
Title: Re: Resistor colour codes
Post by: Lawrence on December 09, 2019, 09:20:34 PM
or use this

https://www.digikey.co.uk/en/resources/conversion-calculators/conversion-calculator-resistor-color-code-5-band (https://www.digikey.co.uk/en/resources/conversion-calculators/conversion-calculator-resistor-color-code-5-band)
Title: Re: Resistor colour codes
Post by: jpendle on December 09, 2019, 11:31:32 PM
I have never bothered with colour codes and my job is in electronics manufacturing.

Once everything went surface mount, the colour codes went away. Once you've got 0201 parts on a board it all becomes moot  :D

Regards,

John P
Title: Re: Resistor colour codes
Post by: The Q on December 10, 2019, 07:46:53 AM
The common "naughty" version above was that told at RAF Locking No1 Radio School. (along with a formal "nice" version).

We still have stuff coming in for service and repair that was built with conventional resistors, and often early prototypes are built with conventional resistors. But almost all our production stuff is surface mount now..

Must get back to work.. measuring the zero Ohms resistance of a calibrator at the moment. It should be about,  0.000 023 and a little bit Ohms. That value is taken into account when calibrating the Zero on Multimeters.
Title: Re: Resistor colour codes
Post by: chrism on December 10, 2019, 08:08:27 AM
Must get back to work.. measuring the zero Ohms resistance of a calibrator at the moment. It should be about,  0.000 023 and a little bit Ohms.

That accurate, eh?
What if the "little bit" is too little or too not little?
 :D
Title: Re: Resistor colour codes
Post by: The Q on December 10, 2019, 08:24:02 AM
Must get back to work.. measuring the zero Ohms resistance of a calibrator at the moment. It should be about,  0.000 023 and a little bit Ohms.

That accurate, eh?
What if the "little bit" is too little or too not little?
 :D
Less would be better and probably on a new Calibrator which therefore has new relays in it. Most of the figure is made up of relay contact resistance and PCB to connector resistance.
If it strays too high then a relay change is normally the first point of attack..

I've now measured the lead resistance 0.000,001,8 Ohms and am waiting for the measured resistance of the calibrator Zero, take the above from the next measurement and I have the result.

After that I have left to measure, 10K Ohms Down to 1 Ohms with similar accuracy, each value is measure 20 times, 10 forward current, 10 reverse Current. With intermediate measurements thats 200 measurements to go and that will be this calibrator finished except for putting a reference DMM on it to check the correction file is correct..

In all a calibrator of this type takes 2 man days of work..

Initial results look like it being about 0.000,021,9 Ohms
Title: Re: Resistor colour codes
Post by: TrevL on December 11, 2019, 04:07:17 PM
Please forgive my ignorance, but how do you know when you pick up a resistor, it is the right way round to read the colours off correctly?
Title: Re: Resistor colour codes
Post by: emjaybee on December 11, 2019, 04:17:34 PM
I too was taught the :censored: non PC version using Violet not purple back in the early 70's at Artificer training in the RN.

 :censored: Boys  :censored: our young girls but   :censored: go without.

My father taught me a similar one that he was instructed with in RAF National Service.

 :censored:  :censored:  :censored: our young girls but  :censored:  go without

Black            Brown          Red           Orange  Yellow   Green  Blue   Violet   Grey  White

 :-[
Title: Re: Resistor colour codes
Post by: Nigel Cliffe on December 11, 2019, 04:45:17 PM
Please forgive my ignorance, but how do you know when you pick up a resistor, it is the right way round to read the colours off correctly?

Because there are limited combinations for the tolerance bands - either silver or gold.  Those go on the right, thus the resistor is the "right way round".   

The simple way is the 10 (or less) digital multimeter.  Gives the right answer every time.       
Colour codes date from an era when components were larger, meters were expensive and measuring resistance on them was a slow task.  Colour codes are like log-tables and/or slide-rules for multiplication: made obsolete by advancing technology. 


- Nigel
Title: Re: Resistor colour codes
Post by: themadhippy on December 11, 2019, 05:04:50 PM
Quote
Because there are limited combinations for the tolerance bands - either silver or gold.
Brown,red ,green ,blue, violet and  grey  are also valid tolerance band colours.In general you can tell by the spacing between the bands,the spacing between the value and tolerance bands are wider than the spacing between the value bands
Title: Re: Resistor colour codes
Post by: sprogman on December 11, 2019, 05:22:47 PM
Please forgive my ignorance, but how do you know when you pick up a resistor, it is the right way round to read the colours off correctly?

For run of the mill resistors there are only certain valid combinations see https://www.electronics-notes.com/articles/electronic_components/resistors/standard-resistor-values-e-series-e3-e6-e12-e24-e48-e96.php (https://www.electronics-notes.com/articles/electronic_components/resistors/standard-resistor-values-e-series-e3-e6-e12-e24-e48-e96.php) E12 and E24 are the most common. I believe (could be wrong, it's been a long time) that it should not be possible to read the colour code from the wrong end and get a valid result.
Title: Re: Resistor colour codes
Post by: Dorsetmike on December 11, 2019, 06:49:19 PM
Another thing with resistors is what are termed "preferred values", the page linked below explains things, probably the most common values are the E12 range, just over half way down the page, with a very useful diagram 2.2.1
Which shows how a 10% tolerance defines the spacing between values;

http://www.learnabout-electronics.org/Resistors/resistors_05.php?sa=X&ved=2ahUKEwik-IbZnq7mAhW6TBUIHSz1BhYQ9QF6BAgLEAI (http://www.learnabout-electronics.org/Resistors/resistors_05.php?sa=X&ved=2ahUKEwik-IbZnq7mAhW6TBUIHSz1BhYQ9QF6BAgLEAI)
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